Bayesian Tree Ensembles for Data Fusion and Causal Inference // Bayesian tree ensemble models for data fusion and causal inference. The main model FusionForest() combines data from a randomised controlled trial and an observational study using separate tree forests, allowing for unmeasured confounding in the observational data. Continuous and (interval-)censored survival outcomes are supported. Posterior summaries of treatment effect estimates and interpretable linear projections are provided.